Retractable boring head for mining machines



Jan. 1, 1957 H. E. SMITH 2,776,124

RETRACTABLE BORING HEAD FOR MINING MACHINES Filed Jan. 15, 1956 s Sheets-Sheet 1 1 I 37 \X J 4,

as J 42 g a4- a9 3a 1 36 23 i7 6H 5 r VI 0 56 2a 59 if 5a 45 I 54 24 1 53 4 57 25 72a 2 24a.

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1E1 I a7 F 1 INVENTOR.

.Herman E. Smith ATTORNEY H. E. SMITH RETRACTABLE BORING HEAD FOR MINING MACHINES Jan. 1, 1957 5 Sheets-Sheet 2 Filed Jan. 13, 1956 llll'll'lllllllll llllIllllllllllIlllll II n i ATTORNEY Jan. 1, 1957 H. E. SMITH RETRACTABLE BORING HEAD FOR MINING MACHINES Filed Jan. 1a, 1956 3 Sheets-Sheet 3 ATTORNEY United States Patent RETRACTABLE BORING HEAD FOR MINING MACHINES Herman E. Smith, Park Forest, 111., assignor to Goodman Manufacturing Company, Chicago, Ill., a corporation of Illinois 7 Application January 13, 1956, Serial No. 558,877

2 Claims. (Cl. 262.-7)

This invention relates to improvements in mobile mining machines of the boring type wherein one or more rotary boring heads, having a plurality of radial cutter carrying arms, are forced into a face of standing mineral such as coal. Such machines are commonly provided with means for reducing the outer diameter of the boring heads to aid in permitting the machine as a whole to be withdrawn from the bore produced by it and moved from place to place in the mine. One means previously devised for collapsing the 'outer ends of the radial arms of the boring head is illustrated in Cartlidge co-pending application, Serial No. 463,867, filed October 22, 1954 on Retractible Boring Assembly, now Patent No. 2,736,542, and consists broadly in hinging the radial arms on the boring head hub so that the arms may be swung forward- 1y toward and away from the axis of the boring head. This type of hinged arm structure presents diflicult problems in providing suitable means for fully enclosing the arm-hinging mechanism within the hub for retention of lubricant, and also for protecting said mechanism from ingress of dirt, grit, Water or the like.

Sealing against the ingress of water is'particularly important when the machine is operating in a mine face inasmuch as sprays of water are played upon the head and the face to control the dust arising from the cutting and gathering functions of the head.

The principal object of the present invention is to provide an improved boring head structure of the character described, having a simple seal for the hinge-actuating mechanism effective in all permissible positions of hinged adjustment of the arms relative to the hub and being particularly effective to exclude water from sprays or the like.

Other objects of the invention will appear as the following description proceeds.

The invention may best be understood by reference to the accompanying drawings, in which:

Figure 1 is a side view, in part section, of a cutter head employing a preferred embodiment of the present invention, together with journal bearings for the cutter head forming part of a mobile mining machine;

Figure 2 is a plan view in partial section of the head taken on line 2-2 of Figures 1 and 4;

Figure 2a is an enlarged fragmentary view of Figure 2 taken in the area 2a of the latter figure;

Figure 3 is a partial sectional view, showing the grease passages, taken on line 33 of Figures 1 and 4;

Figure 4- is an enlarged detail section of the seal mechanism shown in Figure 1 when the arm is in extended or working relationship to the hub; and

Figure 5 is an enlarged detail section similar to Figure 4 but showing the arm in retracted relationship to the hub.

Like parts are referred to by like reference characters throughout the drawings.

Referring now in more detail to the embodiment shown in the drawings, the mobile mining machine has, as usual, a gear housing 21 with a journal bearing 22 em- 2 ,776,124 Patented Jan. 1, 1957 'ice bracing a hollow drive shaft 23. The rotatable head includes a hollow hub 24 with a backwardly extending sleeved portion 26 splined as at 27 onto the drive shaft and having an inwardly extending flange 28 connected by cap screws 29 to the end of the drive shaft. Thus, the drive shaft 23 is effective to rotatably drive the hub 24.

The hub 24 includes two hollow radially open extensions 24a, 24a, each having opposed pairs of transversely spaced ears 31, 31 at their outer ends. A pivot pin 32 extends transversely between each pair of cars 31, 31, as best shown in Fig. 2, and pivotally supports a radially extending arm 33 near the inner end thereof. Each arm 33 is retractible or collapsible by hinged movement about pivot pin 32 toward and away from the axis of rotation of the hub. As seen in Figure 4, each extension 24a terminates approximately coplanar with the axis of the pivot pin 32. The side faces 30 of the arm 33 adjacent the pivot pin extend into close-fitting engagement with the inner surfaces 30a of said ears. The purpose of this construction will presently be more fully described.

Each of the arms 33 has mounted, as by means of bolts 34, forwardly projecting brackets 36, 37 on which are mounted cutter bit clusters 38, 38a for cutting kerfs 39 and 41 respectively in a mine face (see Fig. 1). The brackets 36 may as usual be provided with outwardlyacting wedge surfaces 42 for breaking up the outstanding core 43 in the manner indicated in Fig. 1.

T he hub 24 is also provided with transverse extensions 45 (only one shown, in Fig. 1) disposed at right angles to the hollow extensions 24a, and having supporting brackets 46 fixed thereto by bolts 47, each bracket having a cutter bit cluster 48 effective to cut an inner circular kerf 49 as shown in Fig. 1. Each of the brackets 46 has an outwardly-acting Wedge surface 51 (similar to 42) effective to break up the core 52.

At the forward end of the hub, and secured thereto by cap screws 53 is a conical, helically threaded burster member 54 with pilot bit means 56 to make the initial entry into the mine face and then break up the inner annular core 57 (Fig. 1).

As shown in Fig. l, the interior of the hub 24 has an axial bore 58 within which a slide member 59 is mounted for forward and backward reciprocation. An axially disposed actuating shaft 61 is connected to the slide 59 by tapered bearing coupling means generally designated 62 so that the slide member may be moved forward and backward in the bore while the hub is rotating without requiring rotation of the shaft 61, the latter preferably comprising a control rod which is not rotatable. A similar control mechanism is disclosed in co-pending application, Serial No. 463,867, new Patent No. 2,736,542.

The slide member 59 is pivotally connected through a pair of links 63 with inwardly extending portions 55 of the hinged arms 33.

One of the principal features of the present invention is that each arm 33 is closely fitted for hinged movement within the hollow extension 24a and between the cars 31, 31, in order to seal the hub against the entrance of dirt, grit and water and to prevent the loss of lubricant. For this purpose, as best shown in Figs. 4 and 5, the inner end portion of each arm 33 is provided with front and rear arcuate surfaces A and B struck from the axis of pivot pin 32. Cooperating with surface A is a wiper assembly generally designated 64, while cooperating with surface B is a somewhat similar wiper assembly generally designated 66. Enlargements of wiper assemblies 64 and 66 are shown in Figs. 4 and 5 where it will be seen that wiper assembly 64 includes a main backup plate 67, with a grease-resistant, rubber-like wiper sheet 69 similar to neoprene interposed between said plate and the end surface 69a of the hub extension 24a; the whole wiper arrangement being mounted on the outer face 69a by cap screws 71, The lowerI- end of surface A terminates at a heel.68 projecting from. arm-33 adjacenttheextension 55 of the latter. The wiper sheet 69 is initially assembled so as to be pressed firmly into engagement with the surfacef-Ay and'g when the arm 33-is moved to the operative position shown-zin Figs; 1 and 4, the:wipeh sheet '69 is compressed from beneath, between the heel 68'and the back-upplate 67; and squeezed: more positivelyinto sealing engagement with the surface Th'e wiper'assembly" 66- at the rear of the hub-extension 24a -is similarly constructed andar-rang'ed, differing in the'respect that it is:relatively short in the dimension shown in Figsti4 and: 5; also, itsheel 60 (corresponding to 69) is on'the outside ofthe hub andbears downwardly-on a rubberlike wiper 65" (corresponding to 69) in :order'to increase the sealing pressure between the wiper and the surface B when the arm 33 is in the operative=positionof- Fig. '4.

Each end:bearing surface 30 on arms 33 has formed therein a "groove 81 concentric with the pin 32. As shown in Fig. 4, in the particular'embodiment illustrated, the inner end of the arm 33' is truncated, -along-:a line 100, to provideworking room for the slide59; as a result, it will be seen that the groove is opened up-by the surface 100, and, in order to close it to retain'grease, two stoppages in the form of welds are provided at 86 and 87. As will be-developed later herein, these grooves retain grease for sealing the adjacent bearing surfaces 30 and 30a.

As-shown in Fig.- 3, each groove'81 has its'own individual grease supply means including intersecting passages 82-and 83 and grease fitting 84;

A grease; preferably'of the water-proof type, is intro dueed through the above-mentioned passages, to each of the grooves 81,whence it spreads'radially' inward and outward to the clearance between surfaces 30', 30a,- as indicated by the numeral 101 in Fig. 2a, and is effective inall positions of the arm to prevent'loss-of lubricant and ingress of dirt and water.

The groove 81 is preferably formed as far as practicable from thepin 32, relatively close to the inner sealing surfaces69band 65b of the rubberlike wiper rings, so as to minimize the distance C over which the grease must spread to provide an adequate seal (see Figure 2).

Thus, it will be'seen that a complete, even air and fluid tight seal, is eifected between the'arm' 33 and the hub -at all relative positions therebetween. Specifically, the seal may be traced as follows in Fig. 2: Along the forward portion of the hub, from E to F, the seal will be effected by wiper 69; along one side, that is from F to-Ltheseal will follow three paths, first, from F to G which is across the surface Cabove-mentioned, second, around the groove from G to H, and third, from H'to J which is across the surface D above-mentioned. At

this point,it*should be" emphasized that the groove 81 need' not necessarily be concentric with the pin 32 but may follow any continuous path-from G to H between the surfaces 29, 30; along the rearportion of the hub, from J to K, the seal will be effected by wiper 65; and, along the-second side, from K to E, the seal will be effected in the same manner as described for the first side.

Plugs 72 provide closures for openings 72ain'the ears 31;toaiford access to the pivot pins 73 of links 63, for final assembly of the parts, said pins being inserted through those access openings when the slide member 59 is maintained in the position of Fig.1.

In operation of the machine, it will be understood that the hinged arms 33 are normally extended in a generally perpendicular relation to the rotationalaxis of the boring head so as to cut the several circular kerfs at maximum diameter, as shown in Fig. 1. In this relation,- during operation, the wiper assemblies and 66 are compressed to keep water and dirt-out of the hub. When it isdesiredto collapse the hinged arms forwardlyto reduce the overall'diameter of the boring head, the central shaft 61 it retracted by suitable power means (not shown) at the rear end of the drive shaft, to move the slide member 59 and links 63 to the rear.

As shown in Fig. 1, stop means are provided for limiting rearward hinged movement of the arms 33 relative to the hub, in the form shown,said stop means consisting of a pair of forwardly facing blocks 75 mounted on radial extensions'76of e'ar's'31, and co-acting blocks 77mounted on lugs 78 extending from opposite sides of the hinged arms. The contact faces of the blocks 77 are-generally wedge 'shaped as shownto' crush any loose material that might be caught between the faces of the blocks.

Although I have shown and described a certain embodiment of my invention, I do'not wish to be understood as limiting myself to the exact construction shown and described but that various changes and modifications may be made without departing from the spirit and scope of the invention asdefined in the appended claims.

1. In a boring head for mining machines, and in combination with a hollow rotatable hub having a plurality of radially opening extensions, radially extending arms having their innerends pivotally mounted in said extensions for 'hinged adjustment toward and away from the axis-of said hub; means in said hollow hub for causing hinged adjustment-of said arms, each hinged mounting for said arms comprising a pair of spaced ears at opposite sides' of the end opening of its respective projection,'a pivot pin supported atoppo'site ends in said ears,'the side faces of said arm having close fitting, bearing engagement' with' the adjacent ears, the front and rear faces of the arm having arcuate faces struck from the axis of thepivot pita-and wiper members fixed to the rim of the opening between the ears for sealing engagement with the arcuate'facesof the-arms in all permissible positions of hinged adjustment of said arms, the improvement which consists in'providing each of said side bearing faces of said arms with a continuous grease groove along and adjacent-the arcuatefaces and also along and adjacent the outeredge of said bearing faces opposite the adjacent ears; and a grease supply duct communicating with said groove and accessiblefrom the exterior of said hinged mounting.

2. Ina boring head for mining machines, and in combination'wi-th a hollow rotatable hub having a plurality of radially opening extensions, radially extending arms having'their innerends pivotally mounted in said exten sions for hinged adjustment toward and away from the axisofsaid hub, means in said hollow hub for causing hinged adjustment of said arms, each hinged mounting for said arms comprising a pair of spaced ears at opposite sides of the end opening of its respective projections, a pivot pin supported at-opposite ends in said ears, the side faces of said arm having close fitting, bearing engagement-with the adjacent ears, the front and rear faces of-the armhaving'arcuate'faces struck from the axis of thepivot piny-and wiper members fixed to the rim of the opening betweenthe ears-for sealing engagement with the-arcuate faces of the arms in all permissible positions of hinged adjustment of said arms, each of the wiper members-including a sheet of compressible elastic material and a rigid backing member disposed on the side'of said sheettoward which its adjacent arcuate face is moved when the arm is swung toward fully extended position, and each of the arcuate faces having projecting stop ledges along one end thereof adapted to engage-the adjacent sheets under compression against their respective backing plates when the arm is swung into its fully extended position.

References Cited in the file of this patent UNITED STATES PATENTS 2,736,542 Cartlidge Feb. 28, 1956 

